Black flies (Diptera: Simuliidae) in the Galapagos Islands: Native or adventive?

Invasive species are a threat to ecosystems worldwide, but determining if a species is adventive or native is not always straightforward. The black flies that inhabit the Galapagos Islands, long known as Simulium ochraceum, are blood-feeding pests of humans and livestock. They first came to the attention of residents in 1989, suggesting a recent arrival.

Ratio changes in blood-feeding and voltinism in black flies (Diptera: Simuliidae) over a latitudinal gradient in North America north of Mexico.

We explored how the ratio of blood-feeding behaviour-nonfeeding, bird feeding (ornithophily) and mammal feeding (mammalophily)-and voltinism (univoltine and multivoltine) vary over a latitudinal gradient from Alaska to Florida. These two fixed species traits were divided into five mutually exclusive combinations of trait states-nonfeeding/univoltine, ornithophilic/univoltine, mammalophilic/univoltine, ornithophilic/multivoltine and mammalophilic/multivoltine-within each of three datasets (north, east and west). We found a significant association between location (north, east and west) and trait state, which was driven by the large percentage of nonfeeding females in the north.

Tick-Borne Pathogens Associated with Medically Important Ticks in Alabama: A Four-Year Survey.

Tick-borne diseases (TBDs) represent a significant threat to human health in the United States. Based on reported cases of notifiable TBDs to the Centers for Disease Control and Prevention (CDC) the state of Alabama is no exception, yet previously there has been no active surveillance program in place to comprehensively assess the presence and prevalence of tick vectors and their associated TBD pathogens in Alabama. Here we summarize initial findings from a 4-year survey to address this unmet need.

The general architecture of black fly-parasite interactions: Parasitism in lotic systems at a continental scale.

We examined the general architecture of interactions between stream-dwelling larval black flies (Diptera: Simuliidae) and their common parasites in 1736 collections across North America. Mermithid nematodes (family Mermithidae), microsporidia (phylum Microsporidia), and the fungus Coelomycidium simulii Debaisieux (phylum Blastocladiomycota) infected larval black flies. We found similar continental distributions for these three parasite taxa across North America.

Biodiversity of Simulium metallicum sensu lato (Diptera: Simuliidae), a complex of Neotropical vectors associated with human onchocerciasis.

The polytene chromosomes of 130 larvae of the Neotropical Simulium metallicum complex from Brazil, Costa Rica, and Ecuador revealed five cytoforms, including three ('M', 'N', and 'O') that are new and two ('B' and 'J') that represent range extensions of up to 850km. The discovery of three new cytoforms brings the total number in the complex to 17. Cytoforms 'B', 'J', and 'N' are reproductively isolated from one another, and their species status is corroborated by morphological evidence.

The influence of habitat heterogeneity and latitude on gamma diversity of the Nearctic Simuliidae, a ubiquitous group of stream-dwelling insects.

Among the most prominent, large-scale patterns of species richness are the increases in richness with decreasing latitude and with increasing habitat heterogeneity. Using the stream-dwelling larval and pupal stages of North American black flies (Diptera: Simuliidae), we address 3 broad questions about species richness: (i) Does a significant latitude-richness relationship exist? (ii) How does habitat heterogeneity influence gamma diversity? (iii) What is the sign (positive or negative) of the latitude-richness and the heterogeneity-richness relationships? We found no evidence that habitat heterogeneity influences gamma diversity. The estimated peak species richness for black flies in North America was at 50-53°N, which also corresponds with peak generic richness.

The roles of abiotic factors, dispersal, and species interactions in structuring stream assemblages of black flies (Diptera: Simuliidae).

Background: The patterns and drivers of species assemblages represent the core of community ecology. We focus on the assemblages of a single family of ubiquitous lotic insects, the Simuliidae (black flies), of which the larvae play a critical role in resource turnover in steams. We use Mantel tests and null models to tease out the potential influence of abiotic stream conditions, species interactions, and dispersal on the assemblage patterns of larval black flies over two spatial scales (within and across ecoregions) and two seasons (spring and summer).

Morphological differences of symbiotic fungi Smittium culisetae (Harpellales: Legeriomycetaceae) in different Dipteran hosts.

Harpellales (Legeriomycetaceae, Zygomycota) or 'trichomycetes' are fungi that inhabit the digestive tracts of arthropods such as insects, millipedes, and crustaceans. In the current study we examined changes in 5 morphological characters of Smittium culisetae (Harpellales: Legeriomycetaceae) between the two dipteran (mosquito, black fly) hosts reared under 3 different temperatures (17, 22, 30 degrees C). Both host and temperature had a pervasive effect on the linear dimension of trichospores, their generative cells and hyphae width.

Predicting occurrence of the fungal symbiote Harpella colonizing black fly larvae in coastal streams of Alabama and Mississippi, USA.

The environmental conditions governing symbioses are poorly known in aquatic systems. Stream conditions associated with the distribution of the black fly (Simuliidae) midgut symbiote Harpella were investigated in southern Alabama and Mississippi streams. Stream conditions that were most useful in predicting the distribution of Harpella spp.

Do different species of Smittium (Harpellales, Legeriomycetaceae) influence each other in the host gut?

Smittium (Harpellales, Legeriomycetaceae) belongs to a cosmopolitan group of filamentous fungi (Trichomycetes, Zygomycota) that live as obligate commensals in the digestive tract of various marine, freshwater, and terrestrial arthropods. The outcome of the paired introductions of three species of Smittium was investigated within the individual hosts of the mosquito Aedes aegypti (Culicidae: Diptera). In the first set of experiments, the host was inoculated with a single species of Smittium to determine whether hyphae location within the host was species specific.

The effect of temperature and host species on the development of the trichomycete Smittium culisetae (Zygomycota).

We examined the growth and development of the trichomycete Smittium culisetae (Harpellales: Legeriomycetaceae) in the larval hosts Simulium vittatum Zetterstedt (Diptera: Simuliidae) and Aedes aegypti (L.) (Diptera: Culicidae) at three temperatures, 17, 22 and 30 C. Trichospore maturation of Sm.

Laboratory investigations of trichomycete prevalence, abundance and fecundity in a Smittium-simuliid model.

Smittium, the most speciose genus of the "gut fungi" (Zygomycota: Trichomycetes), is found attached to the hindgut cuticle of larval aquatic Diptera. Smittium spp. colonize several host families (e.

In situ studies of algal biomass in relation to physicochemical characteristics of the Salt Plains National Wildlife Refuge, Oklahoma, USA.

This is the first in a series of experiments designed to characterize the Salt Plains National Wildlife Refuge (SPNWR) ecosystem in northwestern Oklahoma and to catalogue its microbial inhabitants. The SPNWR is the remnant of an ancient ocean, encompassing approximately 65 km2 of variably hypersaline flat land, fed by tributaries of the Arkansas River. Relative algal biomass (i.

First report of a trichomycete fungus (Zygomycota: Trichomycetes) inhabiting larvae of Simulium ochraceum sensu lato Walker (Diptera: Simuliidae) from the Galapagos Islands.

A collection of the larval black fly Simulium ochraceum sensu lato Walker was made at six lotic habitats on San Cristobal Island, Galapagos Islands, Ecuador, during May 2003. Sixty-eight larvae were assayed for the presence of gut fungi (Zygomycota: Trichomycetes). A trichomycete, designated as Smittium sp.

The microdistribution of the trichomycete Smittium culisetae in the hindgut of the black fly host Simulium vittatum.

We examined the distribution of hyphae of the trichomycete fungus Smittium culisetae (Harpellales: Legeriomycetaceae) in the hindgut of a larval black fly (Simulium vittatum, cytospecies IS-7) by analyzing its prevalence and relative abundance. Hyphal prevalence was highest in the posterior colon (93.1%) and rectum (86.

Prevalence of the trichomycete fungus Harpella melusinae (Harpellales: Harpellaceae) in larval black flies (Diptera: Simuliidae) across a heterogeneous environment.

A total of 2063 mid- to late-instar larval black flies were collected from 64 stream sites in South Carolina and screened for the presence of the trichomycete fungus Harpella melusinae. Sixteen of 18 host species were colonized by H. melusinae on at least one occasion.

Scale, time, space, and predictability: species distributions of preimaginal black flies (Diptera: Simuliidae).

This study examines species-specific distributions of preimaginal black flies (Diptera: Simuliidae) over two large spatial scales (within and across ecoregions) and two seasons (spring and summer). The study area in the western two-thirds of South Carolina, United States, was divided into three ecoregions (Mountains, Piedmont, Sandhills). The mean correct classification of species distributions among stream sites was 81.